package com.twmacinta.util;

import java.io.*;

/** 
 * MD5OutputStream is a subclass of FilterOutputStream adding MD5
 * hashing of the output.
 * <p>
 * Originally written by Santeri Paavolainen, Helsinki Finland 1996 <br>
 * (c) Santeri Paavolainen, Helsinki Finland 1996 <br>
 * Some changes Copyright (c) 2002 Timothy W Macinta <br>
 * <p>
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * <p>
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 * <p>
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the Free
 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 * <p>
 * See http://www.twmacinta.com/myjava/fast_md5.php for more information
 * on this file.
 * <p>
 * Please note: I (Timothy Macinta) have put this code in the
 * com.twmacinta.util package only because it came without a package.  I
 * was not the the original author of the code, although I did
 * optimize it (substantially) and fix some bugs.
 *
 * @author	Santeri Paavolainen <santtu@cs.hut.fi>
 * @author	Timothy W Macinta (twm@alum.mit.edu) (added main() method)
 **/

public class MD5OutputStream extends FilterOutputStream {
	/**
	 * MD5 context
	 */
	private MD5 md5;

	/**
	 * Creates MD5OutputStream
	 * 
	 * @param out
	 *            The output stream
	 */

	public MD5OutputStream(OutputStream out) {
		super(out);

		md5 = new MD5();
	}

	/**
	 * Writes a byte.
	 * 
	 * @see java.io.FilterOutputStream
	 */

	public void write(int b) throws IOException {
		out.write(b);
		md5.Update((byte) b);
	}

	/**
	 * Writes a sub array of bytes.
	 * 
	 * @see java.io.FilterOutputStream
	 */

	public void write(byte b[], int off, int len) throws IOException {
		out.write(b, off, len);
		md5.Update(b, off, len);
	}

	/**
	 * Returns array of bytes representing hash of the stream as finalized for
	 * the current state.
	 * 
	 * @see MD5#Final
	 */

	public byte[] hash() {
		return md5.Final();
	}

	public MD5 getMD5() {
		return md5;
	}

}

